One reason for the good reproducibility on the group level for model 1, despite only making use of three submaximumimal work rates, can be the span of the HR attained between work rate 1 and 3 (in average 98–137 and 98–150 for males and females, respectively). It is equally important profil benaughty that the utilized ranges of HR from cycle commuting (in average 113–149 and 118–154 for males and females, respectively) are within, or only slightly above, the range of the HR from the work rates in the laboratory (cf. Tables 3 and 5). If instead VO2 would be estimated from higher or lower HR than those established in the laboratory, it is possible that greater test-retest differences would be seen (cf. Fig 1).
A comment on the field heart rates used is that almost half the cyclists were tested in the laboratory at a different time of day compared to their cycle commuting tests. However, McCrory et al. found that within-day variations were not significantly different at the higher activity levels in their study, i.e. normal to fast walking. Thus our population probably had levels of intensity that were high enough to eliminate circadian influences. Another comment favoring a stability in the measurement conditions is that the mean values for the positions of % HRmax used to establish the HR-VO2 relations related well to the expected VO2 relative to VO2max in both sexes .
, and considerably more favourable in relation to using the HR-VO2 method than those indicated by Christensen et al. . There are several explanations for that. The measurements used by Christensen et al. for establishing HR-VO2 regression equations were resting and sitting, as well as three low to intermediate exercise rates on an ergometer cycle (8–100 watt) and three exercise rates on a treadmill, thus altogether eight measurement points. For both the slope and the y-intercept of the regression equations, the measurements at low levels of HR are, under those circumstances, more influential. At the same time it is well known that the HR-VO2 ratios at rest and sitting are quite unstable, resulting in variations in regression equations [11, 25, 41]. 2 and HR will be higher after a certain HR level, which has been termed “flex HR” [12, 42, 43], which could be another reason for the results of Christensen et al. . Furthermore, they mixed the work forms of cycle ergometer and treadmill as bases for the HR-VO2 measures, which is in itself problematic, since the HR response for a given VO2 can differ in these different forms of movement . This creates a greater risk for non-stability in regression equations with repeated measurements. resulted in a mean value of 86 beats per minute. In line with the reasoning in the Introduction (cf. Fig 1) a heart rate close to the endpoint of the spectrum of measurement points forming the regression equation will most probably lead to lower reproducibility. Another potential explanation for their results relates to their use of a heterogeneous sample of predominantly patients and large variations in age, whereas we studied a sample of healthy and physically active middle aged individuals.
Having stated that, one should just remember that , the outside authenticity off our conclusions about other sorts of players are unclear. Thus, in order to forward the general knowledge throughout these respects, there clearly was in reality a need for then education of them matters.
Additionally, we really do not know any single thing towards outside legitimacy of the Hour method about lab when considering industry requirements such given that during years travelling. About three research has examined brand new intensity of years driving using various other Hours tips inside examples of non-regular course commuters [45, 46, 47]. But not, not one ones degree believed that, to own factors such as for example cardio drift that have stretched really works intervals [twelve, 48, 49] otherwise worry because of customers conditions [50, 51], the relationship measured regarding the research can differ whenever in a pattern travelling ecosystem, and this therefore this new shown intensity of course driving could well be wrong. This is the main focus in our further studies.